The present invention relates to an internal vibrator for compacting concrete and having a vibrator housing in which is disposed an eccentric mass and an electric motor for driving the eccentric mass. The electric motor is supplied via a power supply cord, from a transformer, with electric current having a frequency that is greater than line frequency. The power supply cord is disposed at least in part in a protective and operating tube, with a switch being provided in the power supply cord for turning the electric motor on and off.
With the heretofore known internal vibrators, the converters or transformers have been provided as devices that are separate from the vibrators and that at a construction site are connected to a main power supply and to which then the plugs of the power supply cords of one or more vibrators are connected.
It is therefore an object of the present invention to simplify the use and operation of internal vibrators of the aforementioned general type.